linux/drivers/media/platform/coda/coda-h264.c
Philipp Zabel 0eef89403e [media] coda: pad first h.264 buffer to 512 bytes
The bitstream reader needs 512 bytes ready to read to examine the
headers in the first frame. If that frame is too small, prepend it
with a filler NAL.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-03-22 10:06:26 -03:00

51 lines
1.0 KiB
C

/*
* Coda multi-standard codec IP - H.264 helper functions
*
* Copyright (C) 2012 Vista Silicon S.L.
* Javier Martin, <javier.martin@vista-silicon.com>
* Xavier Duret
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/string.h>
#include <coda.h>
static const u8 coda_filler_size[8] = { 0, 7, 14, 13, 12, 11, 10, 9 };
int coda_h264_filler_nal(int size, char *p)
{
if (size < 6)
return -EINVAL;
p[0] = 0x00;
p[1] = 0x00;
p[2] = 0x00;
p[3] = 0x01;
p[4] = 0x0c;
memset(p + 5, 0xff, size - 6);
/* Add rbsp stop bit and trailing at the end */
p[size - 1] = 0x80;
return 0;
}
int coda_h264_padding(int size, char *p)
{
int nal_size;
int diff;
diff = size - (size & ~0x7);
if (diff == 0)
return 0;
nal_size = coda_filler_size[diff];
coda_h264_filler_nal(nal_size, p);
return nal_size;
}